严格分户制种提高蚕种合格率

我站由于全部是原蚕饲育,饲育户数多,消毒防病面广,工作量大,工作环节多,一个作业组内稍有不慎,便难免有一、两户感染上微粒子病,如果并户制种很可能造成大批的烧种.1989年前后因微粒子病超毒大量地烧种,便开始寻找有效的防治方法.先是在作业组内按户抽检100个以上的苗蛾后并批制种,效果并不理想,后来发展到从100个以上苗蛾那天算,连续抽检三天母蛾后并批制种,虽然能够检测出某一户的微粒子病病率,并按病率大小并批制种,但无法判定是否合格,且有可能让人钻空子和增加送检后的超毒种率,直到1995年春季才在全站试行严格分户制种.为了把超毒种率控制到最低限度,避免蚕种因一、两户有毒的作业组并批制种后造成的整批超毒损失,特进行此项试验.     

农村原蚕分户制种微粒子病检疫抽样方案

农村原蚕分户制种微粒子病抽样检查方法是近年来家蚕微粒子病检疫急需解决的新课题。在全面分析农村原蚕微粒子病批内分布状况的基础上 ,提出了农村原蚕分户制种微粒子病抽样检查方案 ,包括并户检查和分户检查两个步骤。通过对实际调查数据进行计算机模拟抽样检查证明 ,该方案在保证检验批质量符合部颁标准的前提下 ,既兼顾了丝茧育农户的利益 ,又兼顾了蚕种场和种茧育农户的利益 ,同时显著减少了集团镜检次数 ,兼顾了蚕种检验部门的利益。     

集团母蛾检查分段袋蛾的优越性

浙江省蚕种微粒子病集团母蛾检查抽样方法,自从1989年实施以来一直沿用至今.多年的实践证明,它是比较科学、合理的抽样方法.本文就杭州检种室的资料作如下统计分析.一、以日为段分段袋蛾的优点制种批从10万蛾扩展到40万蛾后,对有毒场和新办场(村)实行每制种批按发蛾制种日分段袋蛾,以段制种母蛾数作为抽样和集团检查的总体,而无毒场则以制种批作为集团母蛾检查的总体.其优点有如下两个方面:     

家蚕限性斑纹品种省力化制种初报

本试验利用现行家蚕品种限性斑纹的特点,在饲育期鉴蚕,种茧不削茧、不鉴蛹,采用蚕蛾自行破茧发蛾制种,与常规削茧、鉴蛹发蛾制种的过程进行了比较试验,针对试验结果提出了不削茧、不鉴蛹的相应技术管理配套措施,以期减少削茧、鉴蛹人工,提高蚕种品质,降低生产成本,从而推动蚕种生产的省力化进程。     

提高公斤茧制种量的技术措施

原蚕生产的目的是生产蚕种,在提高蚕种质量的前提下,提高克蚁单产和公斤茧制种量是提高经济效益的需要.提高公斤茧制种量,应认真掌握养蚕制种各阶段的关键技术措施,提高原蚕造卵数,提高发蛾率和单蛾产卵量.     

关于提高公斤茧制种量的技术措施

<正> 原蚕生产的目的是要生产蚕种,在注重提高蚕种质量的前提下,提高克蚁单产和公斤茧制种量是蚕种场提高经济效益的需要,要提高公斤茧制种量,就必须认真掌握养蚕制种各阶段的关键技术措施,提高原蚕造卵数,提高发蛾率和单蛾产卵量。     

提高克蚁制种量的技术措施与体会

提高单产（克蚁制种量）是蚕种生产者一直追求的目标。提高单产就是在不增加或少增加投入的情况，依靠加强管理、依靠科学技术进步来获取更多的产出。因此提高克蚁制种量就意味着生产效率和经济效益的提高。 蚕种单产的高低不仅是量的问题，而且与质也紧密相关。克蚁制种量高的品种、批次，一般来说蚕种质量也是很好的。 从技术上讲，提高克蚁制种量的因素有两个，一是确保各发育阶段优良个体数，提高克蚁有效母蛾数。二是提高单蛾产卵量和良卵率。１ 减少各发育期健康个体的损失，提高克蚁有效母蛾率 收蚁头数（克蚁头数）是有限的，任何阶…     

浅谈以户分段制种形式下的即时浸酸方法

目前,蚕种生产单位为了有效地控制微粒子病发生,减少损失,在原蚕区普遍采取以户分段制种,场部生产则采取分区饲养,以区分段的制种形式,这给冷库的即时浸酸处理带来较大的难度。如采用常规的即时浸酸方法,即根据同一饲育批次的日制种量为浸酸单元计算积温,决定即时浸酸适期的方法,则通过以户分段或以饲育区分段制种的微粒子病防治措施形同虚设,而根据同一饲育批次每段的日制蚕种为浸酸单元,计算积     

分户收茧对提高蚕种质量的影响

为了加强防微工作的预知检查力度,提高蚕种的内在质量,我场在以前实行的蚕种分级制种的基础上,今年又采取分户收茧的新办法。通过今春收茧及制种的实践证明,该办法是可行的、有效的。所谓分户收茧,中心思想是对合作育种的种茧进行全程的监控,实行细化、量化管理,达到一户一号、一户一清的目的。在合批制种前,每一户的种茧、种蛹随时随地都可以单独找出。分户收茧主要包括以下三方面的工作:一是养蚕户在上蔟前期将早熟蚕取样,提前送回场内,通过高温调节,促使早熟茧早出蛾,提早进行苗蛾镜检;二是在收茧期间做到一户一号,分户单放,种茧运回场后以户为单位,单独削茧、鉴蛹;三是根     

亚热带蚕区晚秋蚕种生产技术探讨

在亚热带蚕区晚秋季节低温干燥的不良环境中,蚕种生产既要做好防微、桑园除虫、小蚕饲养、原蚕户的选择等工作,还要做好上蔟到蛹复眼着色阶段的技术保护措施,以及发蛾调节温湿度控制、雄蛾保护等,以提高制种质量。     

Detection of cone dysfunction induced by digoxin in dogs by multicolor electroretinography

It is difficult to detect discrete cone function with the present conventional electroretinography (ERG) examination. In this study, we developed contact electrodes with a built-in color (red (644 nm), green (525 nm), or blue (470 nm)) light source (color LED-electrode), and evaluated an experimental model of digoxin in the dog. First, 17 normal Beagle dogs were used to determine which electrode works well for color ERG measurement on dogs. Then, color ERG was performed on seven normal Beagle dogs at various points during a 14-day period of digoxin administration. A single daily dose of 0.0125 mg/kg/day, which is within the recommended oral maintenance dosage range for dogs, was administered orally for 2 weeks. Ophthalmic examination, measurement of plasma concentration of digoxin, and color ERG examination were performed. On first examination, amplitudes of all responses were significantly (P < 0.01) lower with the red, than with the blue and green electrodes during ERG recording. In ERG using the red electrode, the standard deviation was large. According to these preliminary results, the red electrode was not used in the experimental dog model with digoxin. In the digoxin administrated animals, no significant change was observed in the ophthalmic examination findings. The digoxin level increased steadily throughout the dosing period but was always within the therapeutic range for dogs. In rod ERG, no abnormalities were detected with any electrode. In standard combined ERG, decreased amplitude of the a-wave was detected with every electrode. In single flash cone ERG, prolongation of implicit time was detected by color ERG with the blue and green electrodes. In 30-Hz flicker ERG, decreased amplitude was detected only by color ERG with the blue electrode. The decreased amplitude and prolonged implicit time recovered after termination of digoxin administration. Cone dysfunction induced by digoxin in the dog was revealed by multicolor ERG using blue and green LED-electrodes. Multi-color ERG was useful for detecting cone type-specific dysfunction in the dog.     

Immune response in mice infected by Encephalitozoon cuniculi and suppressed by dexamethasone

Several indicators of immune response were observed in immunocompetent mice of the ICR line and those suppressed by dexamethasone upon their experimental infection with the microsporidia of Encephalitozoon cuniculi. The mice were infected by one-shot intraperitoneal administration of 5 x 10(7) pathogenic spores. On Days 7, 14, 28 and 42 after infection, peripheral blood leukocyte phagocytic activity was determined and compared, including phagocytic index and the blastogenic response in spleen cells to mitogenic activation by concanavalin A and phytohaemagglutinin. The results point to the fact that E. cuniculi itself can cause a significant decrease in phagocytic activity of phagocytic leukocytes in the early stages of infection as well as a remarkable decrease in the proliferative response of spleen cells to T-cellular mitogens.     

Ovariectomy by colpotomy in cows.

For the purpose of collecting active ovarian structures for cell culture, unilateral ovariectomy (n = 34 ovaries) was performed per vagina on 17 dairy cows having normal estrous cycles, bilateral ovariectomy was performed on 9 (n = 18 ovaries) dairy cows, and corpora lutea (n = 13) were removed from 11 beef cows having normal estrous cycles. None of the cows was clinically ill after the operation. Nine of 37 cows developed adhesions of both uterine horns and the body of the uterus. Three instruments were used to perform colpotomy. The described surgical technique for removal of the ovaries or corpora lutea is practical and inexpensive, and has low morbidity associated with it.     

鸡群饮水免疫应注意的事项

在规模化、集约化养鸡场,免疫接种较常用的方法是饮水免疫,对适合用饮水法免疫的疫苗,使用饮水法具有省时、高效、简便易行、鸡群应激小等优点,因而深受广大养鸡户的欢迎。在生产实践中,笔者发现有时由于受一些因素的影响,饮水免疫效果不确实,为帮助广大养鸡户搞好饮水免疫,提高免疫效果,现将饮水免疫必须注意的事项总结如下:(1)饮水免疫接种前应了解当地确无疫病流行,被接种的鸡群一定要健康,体质瘦弱、患有其它疾病的鸡不能使用。(2)疫苗的接种途径与免疫效果有直接关系,并非所有的疫苗都适合饮水免疫。饮水免疫接种必须是适合饮水免疫的…     

饲料性氟中毒

本文主要论述了饲料性氟中毒的病因和临床症状，防治及影响畜禽对氮耐受性的因素。